|
Insular Dwarfism
Insular dwarfism, a form of phyletic dwarfism, is the process and condition of large animals evolving or having a reduced body size when their population's range is limited to a small environment, primarily islands. This natural process is distinct from the intentional creation of dwarf breeds, called dwarfing. This process has occurred many times throughout evolutionary history, with examples including various species of Dwarf elephant, dwarf elephants that evolved during the Pleistocene epoch, as well as more ancient examples, such as the dinosaurs ''Europasaurus'' and ''Magyarosaurus''. This process, and other "island genetics" artifacts, can occur not only on islands, but also in other situations where an ecosystem is isolated from external resources and breeding. This can include caves, desert oases, isolated valleys and isolated mountains ("sky islands"). Insular dwarfism is one aspect of the more general Foster's rule, "island effect" or "Foster's rule", which posits that w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elephas Falconeri 4
''Elephas'' is a genus of elephants and one of two surviving genera in the Family (biology), family Elephantidae, comprising one extant species, the Asian elephant (''E. maximus''). Several extinct species have been identified as belonging to the genus, extending back to the Pliocene or possibly the late Miocene. Description Species of ''Elephas'' have distinct bossing of the parieto-occipital region of the skull. The premaxillae bones containing the tusks are tapered. Evolutionary history Relationships of living and extinct elephantids based on DNA, after Palkopoulou et al. 2018.Asian elephants share a closer common ancestry with mammoths (genus ''Mammuthus'') than they do with African elephants (''Loxodonta''). The oldest species attributed to the genus ''Elephas'' is ''E. nawataensis'' from the Late Miocene-Early Pliocene of Kenya, though the validity of this species and its relationship to ''Elephas'' has been doubted. The oldest species widely attributed to the genus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morphology (biology)
Morphology (from Ancient Greek μορφή (morphḗ) "form", and λόγος (lógos) "word, study, research") is the study of the form and structure of organisms and their specific structural features. This includes aspects of the outward appearance (shape, structure, color, pattern, size), as well as the form and structure of internal parts like bones and organs, i.e., anatomy. This is in contrast to physiology, which deals primarily with function. Morphology is a branch of life science dealing with the study of the overall structure of an organism or taxon and its component parts. History The etymology of the word "morphology" is from the Ancient Greek (), meaning "form", and (), meaning "word, study, research". While the concept of form in biology, opposed to function, dates back to Aristotle (see Aristotle's biology), the field of morphology was developed by Johann Wolfgang von Goethe (1790) and independently by the German anatomist and physiologist Karl Fried ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stegodont
Stegodontidae is an extinct family of proboscideans from Africa and Asia (with a single occurrence in Europe) from the Early Miocene (at least 17.3 million years ago) to the Late Pleistocene. It contains two genera, the earlier ''Stegolophodon'', known from the Miocene of Asia and the later ''Stegodon,'' from the Late Miocene to Late Pleistocene of Africa and Asia (with a single occurrence in Greece) which is thought to have evolved from the former. The group is noted for their plate-like lophs on their teeth, which are similar to elephants and different from those of other extinct proboscideans like gomphotheres Gomphotheres are an extinct group of proboscideans related to modern Elephant, elephants. First appearing in Africa during the Oligocene, they dispersed into Eurasia and North America during the Miocene and arrived in South America during the Ple ... and mammutids, with both groups having a proal jaw movement utilizing forward strokes of the lower jaw. These similar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homo Floresiensis
''Homo floresiensis'' , also known as "Flores Man" or "Hobbit" (after Hobbit, the fictional species), is an Extinction, extinct species of small archaic humans that inhabited the island of Flores, Indonesia, until the arrival of Homo sapiens, modern humans about 50,000 years ago. The remains of an individual who would have stood about in height were discovered in 2003 at Liang Bua cave. As of 2015, partial skeletons of 15 individuals have been recovered; this includes one complete skull, referred to as "LB1". ''Homo floresiensis'' is thought to have arrived on Flores around 1.27–1 million years ago. There is debate as to whether ''H. floresiensis'' represents a descendant of Java Man, Javanese ''Homo erectus'' that reduced its body size as a result of insular dwarfism, or whether it represents an otherwise undetected migration of small, ''Australopithecus'' or ''Homo habilis''-grade archaic humans outside of Africa. This hominin was at first considered remarkable for its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Papagomys
''Papagomys'' is a genus of very large rats in the tribe Rattini of the subfamily Murinae, with body masses of . It contains two species, which are known only from the Indonesian island of Flores: * Flores giant rat ''Papagomys armandvillei'' * Verhoeven's giant rat ''Papagomys theodorverhoeveni'' (possibly extinct, only known from subfossil remains) A possible unnamed third species is also known from subfossil remains. Both species have records extending to the early Late Pleistocene. The species are thought to be terrestrial, preferring closed habitats, with ''P. armandvillei'' known to engage in burrowing. They are thought to be omnivores, consuming leaves, fruit and invertebrates. See also * ''Mallomys ''Mallomys'' is a genus of rodent in the family Muridae. The name of the genus is formed from the Greek language, Greek μαλλός, ''mallos'', wool, and μῦς, ''mus'', mouse/rat. These very large rats weigh between and are native to highl ...'' a genus of giant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pigeon
Columbidae is a bird family consisting of doves and pigeons. It is the only family in the order Columbiformes. These are stout-bodied birds with small heads, relatively short necks and slender bills that in some species feature fleshy ceres. They feed largely on plant matter, feeding on seeds ( granivory), fruit ( frugivory), and foliage ( folivory). In colloquial English, the smaller species tend to be called "doves", and the larger ones "pigeons", although the distinction is not consistent, and there is no scientific separation between them. Historically, the common names for these birds involve a great deal of variation. The bird most commonly referred to as "pigeon" is the domestic pigeon, descendant of the wild rock dove, which is a common inhabitant of cities as the feral pigeon. Columbidae contains 51 genera divided into 353 species. The family occurs worldwide, often in close proximity to humans, but the greatest diversity is in the Indomalayan and Australasi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dodo
The dodo (''Raphus cucullatus'') is an extinction, extinct flightless bird that was endemism, endemic to the island of Mauritius, which is east of Madagascar in the Indian Ocean. The dodo's closest relative was the also-extinct and flightless Rodrigues solitaire. The two formed the taxonomic rank, subtribe Raphina, a clade of extinct flightless birds that are a part of the group that includes Columbidae, pigeons and doves (the family Columbidae). The closest extant taxon, living relative of the dodo is the Nicobar pigeon. A white dodo was once thought to have existed on the nearby island of Réunion, but it is now believed that this assumption was merely confusion based on the also-extinct Réunion ibis and paintings of white dodos. Subfossil remains show the dodo measured about in height and may have weighed in the wild. The dodo's appearance in life is evidenced only by drawings, paintings, and written accounts from the 17th century. Since these portraits vary considerabl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tiger Snake
The tiger snake (''Notechis scutatus'') is a large and highly venomous snake of southern Australia, including its coastal islands and Tasmania. These snakes are often observed and locally well known by their banding, black and yellow like a tiger, although the species can be highly variable in colouration and patterning. All populations are classified within the genus ''Notechis'' (Elapidae). Their diverse characteristics have been classified either as distinct species or by subspecies and regional variation. While tiger snakes are usually ground-dwelling, they are able to swim as well as climb into trees and buildings. Taxonomy The genus ''Notechis'' is in the Elapidae, elapid family, venomous snakes with fixed front fangs. The classification of this genus is given as a single and highly variable species, ''Notechis scutatus'', or a second species ''Notechis ater'', and by an arrangement of subspecies or regional morphs. A 2016 genetic analysis showed that the closest relat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermoregulation
Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperature as its own body temperature, thus avoiding the need for internal thermoregulation. The internal thermoregulation process is one aspect of homeostasis: a state of dynamic stability in an organism's internal conditions, maintained far from thermal equilibrium with its environment (the study of such processes in zoology has been called physiological ecology). If the body is unable to maintain a normal human body temperature, normal temperature and it increases significantly above normal, a condition known as hyperthermia occurs. Humans may also experience lethal hyperthermia when the wet bulb temperature is sustained above for six hours. Work in 2022 established by experiment that a wet-bulb temperature exceeding 30.55°C caused uncompensab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Generation Time
In population biology and demography Demography () is the statistical study of human populations: their size, composition (e.g., ethnic group, age), and how they change through the interplay of fertility (births), mortality (deaths), and migration. Demographic analysis examine ..., generation time is the average time between two consecutive generations in the lineages of a population. In human populations, generation time typically has ranged from 20 to 30 years, with wide variation based on gender and society. Historians sometimes use this to date events, by converting generations into years to obtain rough estimates of time. Definitions and corresponding formulas The existing definitions of generation time fall into two categories: those that treat generation time as a renewal time of the population, and those that focus on the distance between individuals of one generation and the next. Below are the three most commonly used definitions: Time for a population to gro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gestation Period
In mammals, pregnancy is the period of reproduction during which a female carries one or more live offspring from implantation in the uterus through gestation. It begins when a fertilized zygote implants in the female's uterus, and ends once it leaves the uterus. Fertilization and implantation During copulation, the male inseminates the female. The spermatozoon fertilizes an ovum or various ova in the uterus or oviducts, and this results in one or multiple zygotes. Sometimes, a zygote can be created by humans outside of the animal's body in the artificial process of in-vitro fertilization. After fertilization, the newly formed zygote then begins to divide through mitosis, forming an embryo, which implants in the female's endometrium. At this time, the embryo usually consists of 50 cells. Development After implantation A blastocele is a small cavity on the center of the embryo, and the developing embryonary cells will grow around it. Then, a flat layer cell forms on the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolution (journal)
''Evolution: International Journal of Organic Evolution'', is a monthly scientific journal In academic publishing, a scientific journal is a periodical publication designed to further the progress of science by disseminating new research findings to the scientific community. These journals serve as a platform for researchers, schola ... that publishes significant new results of empirical or theoretical investigations concerning facts, processes, mechanics, or concepts of evolutionary phenomena and events. ''Evolution'' is published by Oxford Academic (formerly by Wiley) for the Society for the Study of Evolution. Its current editor-in-chief is Jason Wolf of the University of Bath, United Kingdom. Former editors-in-chief The journal was founded soon after the Second World War. Its first editor was the systematic ornithologist Ernst Mayr. * Ruth Geyer Shaw, July 2013 – 2017 * Daphne Fairbairn, 2010 – June 2013 References External links * at Oxford AcademicForm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
